For the ultimate in cold-weather comfort when snowholing, bivvying or tackling Himalayan peaks, the Crux Torpdedo 900 offers fully waterproof construction. The outer is made from eVent waterproof and breathable fabric, and the seams are all taped, so the bag is completely waterproof except for the base of the zip and the hood opening. Inside you get 850+ fill power down with vertical V-tube baffles and slant wall baffles to limit cold spots. The zip is a very chunky Riri Aquazip to keep water out, and this has a wide and well-stuffed baffle on the inside to reduce cold spots. The shoulder baffle is also wide and well-filled, so when you’re tucked inside this feels really cosy. It comes in a roll-top stuffsack and has an impressive weight and packed size for its features. At this price the Crux Torpedo 900 is specialist kit, but for some situations it is the only choice.